Tolkien wrote a poem called 'The Hoard', which is to be found in 'The Adventures of Tom Bombadil', 'The Tolkien reader' etc. In this poem a dwarf takes possession of a hoard of elven gold. He grows old, guarding it while not doing anything useful with it, till he is killed by a young dragon 'His bones were ashes in the hot mire'. The dragon in turn ages on his hoard, in fear of thieves. He is ended by a young warrior, who becomes a great king, whose rule becomes unjust as he ages along with the hoard. His enemies kill him and destroy his kingdom; the hoard is lost. It's still there, 'In an old rock, behind doors that none can unlock'.

This poem was preceded by an earlier version published in the 30s, which was itself preceded by quite a different poem published in the 20s, called. 'Iuomonna Golde Galdre Bewunden', which can be found in Douglas Anderson's 'The Annotated Hobbit', pp.335-337. Shippey wrote an extremely illuminating paper on these versions of 'The Hoard', published in his anthology 'Roots and Branches - Selected papers on Tolkien'.

Shippey talks of Thorin's falling under what Tolkien calls 'the dragon sickness' - that is, the same desire for gold that afflicted Smaug, and also the Master of Lake-town. He also says 'Thorin also comes under the 'bewilderment' of the hoard, which betrays him into injustice and almost into treachery...' (p.342)